Fertilizer Replacement Value Research Articles

N credit of soybean to a following corn crop in central Ontario

Field studies were conducted to determine the nitrogen (N) fertilizer replacement value (NFRV) when soybean (Glycine max [L.] Merrill) preceded corn (Zea mays L.) in the rotation (S-C), compared to corn preceding corn (C-C). Large, replicated blocks of soybean and corn were established in 1993 and 1994 near Elora, Ontario. In the following year, each large block was subdivided into smaller plots. Fertilizer N was applied at six rates from 0 to 200 kg N ha−1 to the second-year corn crop. Corn grain yield responses to fertilizer N were fitted by quadratic regression. Maximum economic rate of N was calculated for each crop sequence and NFRV's were determined. Corn yields were consistently higher when grown after soybean (S-C) than after corn (C-C). Maximum corn yields were 10.4 and 12.3 Mg ha−1 in 1994 and 1995, respectively. NFRVs for S-C, compared to C-C, were 41 and 59 kg N ha−1 in the two years. As a result of these studies and numerous other experiments, recommended fertilizer N rates have been changed to 30 kg N ha−1 less for S-C than for C-C in central Ontario. Key words: Nitrogen credit, corn, soybean, fertilizer N, replacement value, crop rotation

Response of alfalfa to inoculation with Penicillium bilaii (Provide)

Yield and phosphorus (P) uptake response of alfalfa (Medicago sativa L.) to inoculation with Penicillium bilaii (Provide) at varying rates of P fertilizer, was determined in small- and large-plot experiments located in the Dark Brown, Black or Gray soil climatic zones of Saskatchewan and Alberta from 1994 to 1996. Soil at the sites contained low to medium levels of available P. In the establishment year of the small-plot experiments, inoculation of alfalfa with P. bilaii increased yields and P uptake by 3 to 18%, when averaged across P fertilizer rates. The largest response to inoculation occurred early in the growing season. In the year following establishment, yield and P uptake of inoculated alfalfa averaged 3% greater than uninoculated plants. In the establishment year of the large-plot experiment in 1994 and 1995, yields and P uptake of inoculated alfalfa at 10% bloom were 7 and 26% greater than uninoculated plants, when grown without and with a wheat (Triticum aestivum L.) companion crop, respectively. Unlike the small-plot experiment, alfalfa in the year following establishment did not respond to inoculation performed the previous year. The P credit (P fertilizer replacement value) of P. bilaii inoculation, based on yield response in the establishment year and in the year following establishment, averaged 4.6 kg P ha−1 in the small-plot experiments and 5.3 kg P ha−1 in the large-plot experiments. Tillage cropping practices that conserve water near the soil surface, and inclusion of a companion crop, may increase the probability of alfalfa response to P. bilaii inoculation as well as the efficacy of that response. Key words: Medicago sativa, Penicillium bilaii, Rhizobium meliloti, Triticum aestivum, phosphorus

97/05136 Treatment of wastewater with high concentration of organic matters by catalytic wet oxidation method. II. Study of reaction conditions: Du, H. et al. Shuichuli Jishu, 1997, 23, (3), 160–164. (In Chinese)

Cover crops (CC) may play an essential role in the recycling of nutrients in organic farming systems with cereals. Harvest time of cereals and management of straw in the field can affect the growth of CC and subsequent nitrogen (N) fertiliser replacement value (NFRV) in the following crop. This study investigates 1) the effect of harvest time, 2) cutting height of straw and 3) straw removal from the main crop on CC growth, composition, uptake and NFRV in the following crop and 4) the effect of CC harvest in autumn on the NFRV in the succeeding crop.A CC mixture of mainly red clover, with chicory and ryegrass was sown under a spring barley crop in 2017, and replicated in 2018. Four strategies of barley harvest were conducted: 1) early harvest as whole crop or 2) early harvest of the upper parts only, 3) at maturity with straw removed or 4) at maturity with straw left on the field surface. Subsequently, CC and high stubbles of left straw were harvested and removed in autumn in half of the field replicates. The residual effect was measured in spring barley in the succeeding year.The CC aboveground biomass dominated by the clover had an N uptake for both years of 40−77 kg N ha−1. Variability was significant between years but not caused by the harvest time or by straw management. In the succeeding year, residues from barley and CC could replace 61−85 kg N ha−1 of mineral N fertiliser, which were mostly derived from CC roots and stubble. High straw stubble left (40 cm length) significantly reduced the NFRV of CC shoots by 20%.Root residues (including barley and CC roots) contributed a substantial N supply to the following crop irrespective of aboveground CC biomass. The availability of N derived from CC shoot mineralisation differed significantly in the two years and was also influenced by straw left from the previous crop.

Soybean nitrogen contribution to corn and residual nitrate under conventional tillage and no-till

Soybean (Glycine max L. Merill) can produce high-N residues that may benefit subsequent corn (Zea mays L.) production, but the degree of benefit is often unpredictable and may be related to tillage methods. This study investigated the effects of conventional-tillage (CT) and no-tillage (NT) on fertilizer replacement values for corn in a corn-soybean rotation. Field experiments were conducted for two growing seasons on two soils, a Ste. Rosalie clay (Humic Gleysol), and an Ormstown silty clay (Humic Gleysol). Continuous corn, corn following soybean, soybean following corn, continuous soybean, and three levels of fertilizer N (0, 90, 180 and 0, 20, and 40 kg N ha−1 for corn and soybean, respectively) were compared. Tillage did not effect yield or N uptake consistently. Corn grain yields and N uptake were greater following soybean than following corn. Soybean provided N fertilizer credits ranging from 40 to 150 kg N ha−1, which was greater than the residual NO3 in the soil prior to planting. Credits were greater in the year with higher corn yields and lower previous winter precipitation resulting in greater NO3 carryover. Tillage effects on N credits from soybean differed between the sites. Consequently, N contributions of soybean to corn could not be related to tillage method or soil type. Key words:Zea mays L., Glycine max L. Merill, rotations, grain yield, N uptake, tillage, fertilizer N

Yield and Green‐Manure Benefits of Interseeded Legumes in a High Desert Environment

AbstractRelay intercropping legumes into vegetable crops provides cover and green‐manure benefits to subsequent crops, but has not been adequately researched in high desert regions. This study evaluated the dry matter, N yield, effect on a subsequent forage sorghum [Sorghum bicolor (L.) Moench] crop, and estimated fertilizer‐replacement value (FRV) of several legumes interseeded into sweet corn (Zea mays L.). The study took place under furrow irrigation in north‐central New Mexico (study site elevation, 1737 m) on a Fruitland sandy loam (coarse‐loamy, mixed, calcareous, mesic Typic Torriorthent). Five legumes (hairy vetch, Vicia villosa Roth; barrel medic, Medicago truncatula Gaertn.; alfalfa, Medicago sativa L.; black lentil, Lens culinaris Medik.; and red clover, Trifolium pratense L.) were interseeded into sweet corn at last cultivation or blister stage in 1993 and 1994. Corn ears and stover were harvested in August. The following spring, plots were plowed and seeded to forage sorghum. Estimated FRV for the legumes were calculated from regression equations for sorghum dry matter yield as a function of N fertilizer rate. Herbage N yields in the fall were greatest for hairy vetch and barrel medic and, averaged across interseeding dates, ranged from 55 to 64 kg ha−1 in 1993 and 100 to 108 kg ha−1 in 1994. Whole‐plant N yields (herbage + roots + crowns) in May were greatest for hairy vetch, 205 kg ha−1 in 1994 and 172 kg ha−1 in 1995. Seasonal dry matter yield and N uptake of sorghum were greatest following hairy vetch in 1994, and hairy vetch and alfalfa in 1995. Based on seasonal sorghum yield, hairy vetch and alfalfa had the highest FRV, ranging from 78 to 140 kg ha−1 N.

Manure Application Planner (MAP): Software for Environmental and Economical Nutrient Planning

Manure management recommendations and practices should be preceded by a whole-farm, comprehensive manure management plan, but manure planning aids have shortcomings that limit their widespread use. The Manure Application Planner (MAP), version 3.0, is a computer software tool used for developing or assessing manure application plans that meet environmental standards and achieve economic feasibility. Manure source quantity and analyses, field nutrient needs and nutrient sensitivity, and nutrient pricing and application cost information form the main categories of program input. Manure and fertilizer application rates are calculated using a linear programming optimization procedure or entered from a predetermined plan. The linear programming algorithm uses environmental, economic, and logistical constraints in its operation to develop an optimized plan. Or, with a producer's predetermined or existing plan, economic factors (fertilizer replacement value, application costs, and hauling costs) are presented and environmental concerns (excess nutrients) are shown. Output information includes manure and fertilizer application rates, total nutrient quantities of each source needed, excess nutrients applied from the manure, residual N availability for the following year, leftover stored manure (if any), and nutrient costs for each field and the farm with and without the use of manure. The combination of individualized input for each farm and/or field and access to the program's dataset coefficients allows for customized, farm-specific manure management plans.

Nitrogen contribution of field pea in annual cropping systems. 1. Nitrogen residual effect

The nitrogen (N) residual effect of field pea (Pisum sativum L.) to a succeeding non-legume crop was determined in a small plot experiment at Scott, Saskatchewan in the moist Dark Brown soil climatic zone, and in a small plot and landscape experiment near Melfort, Saskatchewan in the moist Black soil climatic zone from 1993 to 1995. The N residual effect, defined as the amount of fertilizer N required for a non-legume crop grown on non-legume stubble to produce the same yield as that of the non-legume grown on field pea stubble, averaged 27 and 12 kg N ha−1 at Melfort and Scott, respectively, in the small plot experiment, and 28 kg N ha−1 in the landscape experiment. Landscape slope position and preseeding tillage did not have a significant or consistent effect on the magnitude of the N residual effect of field pea to the succeeding non-legume crop. The N residual effect, calculated using the difference (economic N rate) method, was presumably due solely to the N benefit, with no non-N benefit contribution. The non-N benefit was effectively marginalized when the crop sequence that included field pea was compared with a reference rotation that included a cereal and an oilseed crop. Based on field pea seed yields and the calculated N residual effect, the N credit (N fertilizer replacement value) of field pea to a succeeding non-legume crop in the moist Black soil climatic zone was 15 kg N ha−1 for every 1000 kg of seed. This is slightly higher than the current recommendation of 5 to 10 kg N ha−1 1000 kg−1 seed. Results from the small plot experiment at Scott indicate that current N credit recommendations for field pea are appropriate for the moist Dark Brown soil climatic zone. Key words: Pisum sativum, Triticum aestivum, Hordeum vulgare, Brassica rapa, Linum usitatissimum, nitrogen residual effect

Economic and Biological Benefits of Intercropping Berseem Clover with Oat in Corn-Soybean-Oat Rotations

Sustainability of Iowa agriculture may require change from predominantly a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation to more diverse cropping systems. Alternative crops are vital for providing temporal diversity. Reincorporating small grains into a three-crop rotation with corn and soybean can provide greater temporal diversity, especially if a forage legume is included as a companion crop. A field study was established in 1991 on a Kenyon (fine-loamy, mixed, mesic Typic Hapludoll) soil to evaluate the economic and biological benefits of an oat (Avena saliva L.) crop underseeded with berseem clover (Trifolium alexandrinum L.) in a three crop rotation. Two rotation treatments were compared: (i) corn-soybean-oat and (ii) corn-soybean-oat intercropped with berseem clover. In 1992, 1993, 1994, and 1995, oat grain yield was not significantly changed when berseem clover was underseeded with the oat crop. However, in 5 yr, oat underseeded with berseem clover produced up to 70% more biomass (harvested material without the grain) than sole-crop oat straw. The biomass (40% oat straw and 60% berseem clover forage) also had adequate digestible material (51%) to be considered as low quality forage. Berseem clover regrowth after oat grain harvest produced an average 1.2 tons/acre of forage, which could have been harvested for hay or left in the field as green manure. During this trial, berseem clover regrowth was left as groundcover and green manure, which contributed an average of 39 lb N/acre to the succeeding corn crop. Corn grain yields following berseem clover were 10% higher over the trial period. Soybean grain yields were the same for both treatments. Intercropping berseem clover with oat returned an average of S39/acre more than sole-crop oat. This study demonstrated both economic and biological advantages for more diverse cropping practices.

Interseeding Legumes into Chile: Legume Benefits to a Following Crop of Forage Sorghum

Hairy vetch (Vicia villosa Roth.), barrel medic (Medicago truncatula Gaerth.), and black lentil (Lens culinaris Medik.) were interseeded into `New Mexico 6-4' chile pepper (Capsicum annuum L.) when plants were 8 to 12 inches tall or 12 to 16 inches tall in 1993 and 1994. Hairy vetch overwintered well both years, whereas barrel medic and black lentil did not. Spring aboveground dry mass yields of hairy vetch averaged 2.11 and 2.57 tons per acre in 1994 and 1995, respectively, while N accumulation averaged 138 and 145 pounds per acre in 1994 and 1995, respectively. Forage sorghum [Sorghum bicolor (L.) Moench] dry mass yield and N accumulation were significantly higher following hairy vetch than following the other legumes or no-legume control. There was no significant difference between forage sorghum yields following barrel medic, black lentil, or the no-legume control. Fertilizer replacement values (FRV) for the legumes were calculated from regression equations for forage sorghum dry mass yield as a function of N fertilizer rate. FRV for hairy vetch were at least 7-times higher than for either barrel medic or black lentil. Hairy vetch interseeded into chile pepper and managed as a winter annual can significantly increase the yield of a following crop compared to a nonfertilized control.

Nitrogen requirements of corn (Zea mays L.) as affected by monocropping and intercropping with Alfalfa (Medicago sativa)

Intercropping perennials with corn has the potential to improve utilization of the growing season over monocropping corn in regions where a substantial portion of the growing season is too cool for corn growth. The biomass potential and fertilizer N requirements of monocropped corn (Zea mays) grown using conventional tillage were compared with those of corn intercropped with alfalfa (Medicago sativa) in 1987 and 1988. The intercropped alfalfa was harvested once prior to planting the corn each spring. Rotation effects on and N fertilizer requirements for monocropped corn following these treatments and also following monocropped alfalfa, were evaluated in 1989 and 1990. During the two years of intercropping for which data is presented, the critical intercropped corn biomass (13.05 Mg ha−1) estimated using a quadratic-plus plateau model, was close to the monocropped corn biomass (13.01 Mg ha−1), but an estimated 83 kg ha−1 more N was required for intercropped corn to reach the critical biomass. Total biomass (intercropped corn and alfalfa) was 25% greater than that of the monocropped corn, and the total N uptake was 55% greater than that by monocropped corn over the two- year period. After rotation to monocropped corn using conventional tillage in 1989, corn biomass averaged over N rates following intercropping or monocropped corn was lower (P=0.01) than following monocropped alfalfa. Critical corn biomass estimated was highest following alfalfa and lowest following monocropped corn, and more N fertilizer was required to attain the critical biomass under continuous monocropped corn in 1989. Corn yields and N uptake values in 1990 were not significantly different among the cropping systems. The N fertilizer replacement values due to intercropping decreased from above 90 kg N ha−1 in the first year of rotation to less than 40 kg N ha−1 in the second year of rotation. Considering the higher potential for total biomass production and rotation benefit, intercropping is a viable alternative to conventional corn monoculture for forage production.

Green Manuring with Clover and Ryegrass Catch Crops Undersown in Small Grains: Crop Development and Yields

Abstract In three field trials in southern Norway, spring wheat (Triticum aestivum L.) or barley (Hordeum vulgare L.) monoculture was compared with crops undersown with Italian ryegrass (Loliun multiflorum Lam.), white clover (Trifolium repens L.) and subterranean clover (T. subterraneum L.) at three levels of N fertilizer. The catch crops were ploughed in in late October, and the after-effect on succeeding spring wheat or barley crops was determined. The catch crops were more competitive in 1986, when rainfall in spring was abundant, than in 1985, when it was low. Ryegrass was stimulated by N fertilizer, whereas the clovers were repressed owing to increased shading. At ploughing, catch-crop biomass N ranged from 17 to 94, 37 to 155 and 41 to 243 kg N ha−1 for ryegrass, white clover and subterranean clover, respectively. Grain yields (mean of N-fertilized plots), respectively, ranged from 83 to 94, 84 to 110 and 84 to 100% of yields in monoculture. The catch crops reduced weeds. The fertilizer replacement value of ploughed-in white clover was 50–60 kg N ha−1 on loam soil without N fertilizer. Fertilizer N given either of the years decreased the grain yield response to white clover. Yet, the grain yield with white clover plus 60 kg N ha−1 exceeded that on plots receiving 120 kg N ha−1 as mineral fertilizer only. On sandy loam, the aftereffect was much smaller, most likely owing to N loss during wet conditions in the spring. The effect of ryegrass was neutral and that of subterranean clover intermediate.

Crop rotation and N fertilization effects on growth, yield, and disease incidence in potato

Crop rotation can be an effective mechanism for reducing disease incidence and contributing nitrogen (N) to succeeding crops. Interactions of plant pathogen suppression and soil nutrient availability may also exist, adding to the cropping system complexity. This study examined the impact of crop rotation, N fertilization, and their interaction on growth, yield, andRhizoctonia solani incidence in potato (Solanum tuberosum L. Norwis). Potato was grown continuously and in two-year rotations with annual alfalfa (Medicago sativa L. Nitro), hairy vetch (Vicia villosa Roth), white lupin (Lupinus albus L. Ultra), and oat (Avena sativa Astro). Fertilizer was banded at potato planting with 0, 45, 90, 135, 180, or 225 kg N ha−1 as (NH4)2SO4. Approximately 58% of continuous potato possessed stem lesions caused byR. solani, but only 12 to 22% of potato stems from other rotations possessed lesions. Tuber dry weight was affected by crop rotation in 1989, a dry year, but not in 1990. Apparent N fertilizer replacement values for hairy vetch, Nitro alfalfa, white lupin, and oat were 65, 43, 26, and 11 kg N ha−1, respectively. All crop rotations studied appeared to enhance potato production by reducing stem infection byR. solani. Vetch and alfalfa provide additional benefits through their N contributions.

Legume Cover Crops as a Nitrogen Source for Corn in an Oat-Corn Rotation

The use of legume cover crops as green manures is a means of reducing the amount of N fertilizer used in corn (Zea mays L.) production, but has not been adequately tested in the upper Midwest. A field study was conducted from 1989 to 1993 near Arlington, WI, to determine the value of legume cover crops in a 2-yr oat (Avena sativa L.)/legume-corn rotation. The objectives of this study were to identify the most productive legume species and planting method to be used with oat, to measure the effect on subsequent corn grain yield, and to evaluate the economic viability of oat/legume-corn rotations. Corn yields following the legumes were compared with those of corn following oat without a legume, using six rates of N fertilizer to estimate the fertilizer replacement value of the legumes. Maximum seeding year N yields (tops and roots) were produced by medium red clover (Trifolium pratense L.) companion seeded with oat, and hairy vetch (Vicia villosa Roth) seeded after oat harvest. Averaged over years, these two cover crop options yielded 118 Ib N/acre in the seeding year. Mean corn grain yields (bushels per acre) following these two legumes were 163 for red clover and 167 for hairy vetch. Estimated fertilizer replacement values of these legumes ranged from 65 to 103 Ib N/acre. Gross margins (2-yr rotation mean) of these oat/legume-corn rotations were $166/acre using red clover and $153/acre using hairy vetch and were similar to those obtained with an oat-corn and continuous corn rotation where corn was grown with 160 Ib fertilizer N. These results indicate a great potential for reducing fertilizer N inputs in corn production by using legume cover crops, without economic penalty for producers who adopt the practice.

Nitrogen Credits in Soybean‐Corn Crop Sequences on Three Soils

AbstractEconomic and environmental incentives to accurately predict corn (Zea mays L.) N requirements emphasize the need to assign appropriate N credits for soybean (Glycine max L.) in soybean‐corn crop sequences. This study was conducted to determine corn response to N and N credits for soybean in crop sequences. The effects of corn‐corn (CC), soybean‐corn (SbC), and soybean‐corn‐corn (SbCC) crop sequences and applied N (0 to 225 kg N ha−1) on corn grain yield, N uptake, and soil NO3 and NH4 concentrations were determined for 4 yr at three sites differing in climatic and soil characteristics. Four‐year mean yields in SbC were 1.4 and 2.2 Mg ha−1 higher than in CC at two sites with nonirrigated silt loam soils, but yield effects due to crop sequence were small on an irrigated sandy soil. Corn response to applied N varied markedly among the three sites and between years at the sites on silt loams soils. Mean corn N uptake in SbC was higher (51 kg N ha−1) than in CC on silt loam soils but not on the sandy soil. Soybean N credits estimated with a fertilizer replacement value (FRV) approach and from the difference in N rates at maximum yield in SbC and CC sequences (DNM) differed markedly among locations and years and ranged from − 22 to 210 kg N ha−1. Soybean provided little N to subsequent crops on sandy soils due to probable loss of residue N through leaching prior to use by the following crop. On silt loam soils, crop sequence effects on yield and N uptake indicate soybean N contributions to subsequent crops; however, fixed value N credits or N credits based on N response data combined over years will seldom accurately predict actual soybean N contributions. Site‐specific diagnostic tests are needed to improve crediting of N supplied by soybean in crop sequences.

Productivity and nitrogen fertilizer requirements of barley in rotation systems in rainfed mediterranean conditions

The productivity of barley was examined, when grown after vetch or fallow or in continuous barley systems, at two locations in Cyprus (250 and 350 mm mean annual rainfall sites), for eight years. Barley was supplied with 0, 30, 60 or 90 kg N ha-1 fertilizer in sub-plots. Barley in the vetch-barley and fallow-barley systems was more productive than in continuous barley systems. Nitrogen fertilizer applied to continuous barley was not sufficient to compensate for the rotation effect that vetch (at both locations) and fallow (at the 250 mm site) had on the subsequent grain yield of barley. At both sites, the optimum N fertilizer rate for grain yield of barley was zero and 30 kg N ha-1 when grown after vetch and fallow, respectively, while after continuous barley systems it was 45 and 60 kg N ha-1 for the low and high rainfall sites, respectively. In comparison to a continuous barley system, the fertilizer replacement value of vetch for the subsequent barley was 60 kg N ha-1, and that of fallow 30 kg N ha-1. Nitrogen and water storage were the major factors contributing to the total rotation effect on barley yield after vetch and fallow, even though other unidentified factors were also involved.

Forage Legume-Small Grain Intercrops: Nitrogen Production and Response of Subsequent Corn

Frost-seeding a legume into an established stand of winter wheat (Triticum aestivum L.) or interseeding a legume into a small grain at planting has potential to provide the benefits of a legume green manure while still allowing for the harvest of a revenue-producing crop. Field studies were conducted at three Michigan locations to quantify N accumulation by alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) frost-seeded into winter wheat or interseeded with oat (A vena sativa L.) and to evaluate the response of a subsequent corn (Zea mays L.) crop to legume and fertilizer N. Cropping sequences included corn following either wheat, wheat frost-seeded with a legume, oat, or oat interseeded with a legume. Corn was planted either no-till following wheat or conventionally (moldboard plow) following oat. Frost-seeding and interseeding alfalfa and red clover had no effect on small grain yield, and stands of alfalfa and red clover were adequate (>13 plants/sq ft) even though N fertilizer had been applied to the small grains. Nitrogen accumulation did not differ among alfalfa or red clover cultivars, and averaged 80, 50, and 116 lb N/acre for alfalfa; and 96, 99, and 176 lb N/acre for red clover frost-seeded into winter wheat at the three locations. When interseeded with oat, alfalfa contained an average of 44 lb N/acre and red clover contained an average of 33 lb N/acre prior to fall plowing. Corn response to the frost-seeded legumes differed among locations due primarily to differences in precipitation during the weeks just prior to and following corn planting. When soil water was adequate, corn grain yields following the small grain seeded with a legume were 4 to 62% greater than following the small grain without the legume. With below-normal precipitation following corn planting, corn grain yields in the legume systems were reduced by 3 to 27%, primarily due to delayed and reduced emergence. Fertilizer replacement values based on grain yield ranged from 0 to 49 lb N/acre for alfalfa and from 0 to 113 lb N/acre for red clover. Response of corn to the preceding legume differed by year, location, and seeding method.